Microbiology Refresher - Bacteria

Question 1

Lobar bacteria is most likely what type of infection?

Answer 1

bacterial infection

Question 2

What are the 3 questions to ask when identifying causative bacteria?

Answer 2

1. what is the source of infection?
2. which pathogenic organism(s) could be responsible?
3. what do I know about the possible gram status of the responsible organism?

Question 3

What type of cell has a cytoplasm, a nucleoid, but no membrane enclosed in a nucleus?

Answer 3

prokaryote (bacteria cell)

Question 4

What contains a single-stranded DNA for reproductive purposes and a circular plasmid DNA?

Answer 4

prokaryote

Question 5

There is enough difference between (1) of humans and bacteria that some antibiotics will impair function of (2) without killing the (3)

Answer 5

1. ribosomes
2. ribosomes
3. host

Question 6

What helps with locomotion is prokaryotes but is not present in all bacteria?

Answer 6

flagellum

Question 7

What allows bacteria to adhere to surfaces such as teeth?

Answer 7

pili

Question 8

What resides in the human microbiota and one or both organisms may benefit from this relationship?

Answer 8

commensal microorganism

Question 9

If both human and commensal microorganism benefit in the relationship, what is it termed?

Answer 9

mutualistic relationship

Question 10

What is a microorganism that is not typically a part of the human microbiota that may or may not not disease?

Answer 10

non-commensal microorganism

Question 11

What can be commensal or non-commensal organisms that cause disease?

Answer 11

pathogen

Question 12

What are the 4 different types of pathogen?

Answer 12

• obligate pathogen
• commensal pathogen
• zoonotic pathogen
• environmental pathogen

Question 13

What type of pathogen needs to be transmitted to survive?

Answer 13

obligate pathogen

Question 14

What type of pathogen may be part of the microbiota but can also cause regular disease and does not require presence of disease to survive?

Answer 14

commensal pathogen

Question 15

What type of pathogen is transmitted to human from animals directly (animal products via an insect vector), and does not require presence of disease to survive?

Answer 15

zoonotic pathogen

Question 16

What type of pathogen includes a pathogenic microorganism that is acquired through exposure in the environment, such as water or soil, and does not require the presence of disease to survive?

Answer 16

environmental pathogen

Question 17

What type(s) of pathogen(s) do not need the presence of disease to survive?

Answer 17

• commensal pathogen
• zoonotic pathogen
• environmental pathogen

Question 18

What type of pathogen is Mycobacterium tuberculosis and why?

Answer 18

obligate pathogen
needs to be transmitted to others, typically through coughing, to survive

Question 19

What type of pathogen is Staphylococcus aureus and why?

Answer 19

commensal pathogen
exists on skin, but can sometimes cause abscesses of the skin & does not require the presence of the abscess to exist or survive

Question 20

What type of pathogen is Yersinia pestis and why?

Answer 20

zoonotic pathogen
was carried by fleas carried on rats that travelled throughout Europe and Asia, causing a plague pathogen

Question 21

What type of pathogen is Legionella pneumophila and why?

Answer 21

environmental pathogen
resides in hot tubs and building water systems - does not require disease to survive

Question 22

Describe obligate aerobes?

Answer 22

requires oxygen for growth

Question 23

Describe obligate anaerobes?

Answer 23

cannot grow in presence of oxygen

Question 24

Describe facultative anaerobes (aerobes)?

Answer 24

prefers oxygen for growth, but can grow in its absence

Question 25

Describe aerotolerant anaerobes?

Answer 25

does not use oxygen to grow, but can tolerate it

Question 26

Describe microaerophiles?

Answer 26

prefers reduced amounts of oxygen to grow

Question 27

What type of infections can occur when bacteria are displaced from their natural body habitat - endogenous acquisition?

Answer 27

anaerobic infections

Question 28

What type of infections can occur when a barrier is broken such as in trauma, infection, or tumor?

Answer 28

anaerobic infections

Question 29

Oxygen may be excluded from the area is which cases?

Answer 29

- obstruction - surgery - trauma with tissue damage

Question 30

What loves dead tissue (non-oxygenated) and are happy to grow in damaged tissue?

Answer 30

anaerobes

Question 31

If there are aerobes or facultative bacteria present simultaneously with anaerobes, anaerobes can further reduce oxygen level in affected area, resulting in (1)

Answer 31

1. more anaerobic growth

Question 32

What can also be acquired exogenously (outside the organism, such as soil)?

Answer 32

anaerobes

Question 33

What are these symptoms of: - putrid odor coming from wound/region - tissue necrosis or gangrene (black discoloration) - gas present in area of infection - skin trauma where normal flora exists but skin barrier is broken (fights, bites, trauma, recent surgical incision) - patient not improving & initial antibiotics had no coverage for this organism

Answer 33

anaerobic infection

Question 34

What type of organisms tend to be more responsive to antibiotics?

Answer 34

gram-positive organisms

Question 35

What has a thick peptidoglycan layer that acts as an easy target for antibiotics and allows for antibiotics to absorb well into it?

Answer 35

gram- positive organisms

Question 36

What type of membrane do gram-positive organisms have?

Answer 36

phospholipid bilayer

Question 37

What is a good example of medication that has typically been used against G+ organisms because it prevents cross-linking of peptidoglycan chains?

Answer 37

penicillin

Question 38

Unlike gram-positive organisms, gram-negative bacteria have what type of cell walls?

Answer 38

thin cell walls

Question 39

What are the cell walls of gram-negative bacteria composed of?

Answer 39

outer membrane (OM) of lipopolysaccharides (LPS) with porin channels connected to layer of peptidoglycan

Question 40

What is a very selective barrier in gram-negative bacteria due to its lipid bilayer?

Answer 40

outer membrane (OM)

Question 41

Because gram-negative bacteria have a selective outer membrane, what happens to antibiotics?

Answer 41

some antibiotics are blocked, so there will be no affect

Question 42

What does this describe in gram-negative bacteria? - allows diffusion of certain molecules based on size - can block out some, but not all, antibiotics - involved in inflammatory mediator release

Answer 42

porin channels

Question 43

A large percentage of bacteria that develop resistance are (1)

Answer 43

1. gram-negative bacteria

Question 44

Changes in (1) of gram-negative bacteria are key in resistance

Answer 44

1. liposaccharide outer membrane

Question 45

What type of bacteria changes so frequently that treatment changes often as well?

Answer 45

gonorrhea

Question 46

What is a gram-negative bacterium that causes cervicitis in women or urethritis in men; patients can be asymptomatic or present with discharge, pelvic pain, and systemic symptoms like fever; and is becoming harder to treat?

Answer 46

Neisseria gonorrhoeae

Question 47

Most gut bacteria is (1)

Answer 47

1. gram-negative

Question 48

These organisms are what type of gram: - staphylococcus - streptococcus - enterococcus - peptostreptococcus

Answer 48

gram-positive

Question 49

Enterobacteriaceae are gut bacteria that are (1)

Answer 49

gram-negative

Question 50

What gram stain is staphylococcus?

Answer 50

gram-positive

Question 51

What gram stain is streptococcus?

Answer 51

gram-positive

Question 52

What gram stain is corynebacterium?

Answer 52

gram-positive

Question 53

What gram stain is mycobacterium?

Answer 53

gram-positive

Question 54

What gram stain is bacillus?

Answer 54

gram-positive

Question 55

What gram stain is clostridium?

Answer 55

gram-positive

Question 56

What are some other pathogenic features of bacteria?

Answer 56

- toxins produced can have devastating effects (toxic-shock syndrome) - capsule or "slime layers" - spores/endospores

Question 57

What makes bacteria "slippery" and can be able to evade phagocytosis?

Answer 57

capsule or "slime layers"

Question 58

Where are spores primarily found in?

Answer 58

gram-positive bacteria

Question 59

What allows bacteria to be dormant and resistant to harsh conditions?

Answer 59

spores

Question 60

You may have to increase effort to kill when (1) are present?

Answer 60

spores

Question 61

What is defined as a collection of bacteria composed of 10 million to 10 billion cells per gram of dehydrated material?

Answer 61

biofilms

Question 62

Biofilms are covered in a matrix that the bacteria assembles as a way of:

Answer 62

**attachment/adhesion** - on surface of teeth **protection** - "like-minded - can withstand some antibitiocs **detachment** - if colony is weakened, it can detach and propagate elsewhere

Question 63

What are characteristics of atypical bacteria?

Answer 63

- lack cell wall - not visible when gram-stained - not easy to culture organism

Question 64

What are these examples of? - Mycoplasma - Chlamydia - Legionella

Answer 64

atypical bacteria

Question 65

What are treatable with antibiotics, such as macrolides and tetracyclines?

Answer 65

atypical bacteria

Question 66

What are big differences in skin colonization even between healthy individuals attributed to?

Answer 66

- age - sex - immune system - genotype - hygiene - occupation - environment - underlying diseases

Question 67

What occur in various areas of the body covered by skin?

Answer 67

bacterial niches

Question 68

What are abundant in moist/humid areas, such as feet and antecubital fossa?

Answer 68

staphylococcus

Question 69

A lot of skin bacteria are what type of stain?

Answer 69

gram-positive

Question 70

Is staphylococcus aerobic, FA, or anaerobic?

Answer 70

facultative anaerobe

Question 71

Is streptococcus aerobic, FA, or anaerobic?

Answer 71

facultative anaerobe or anaerobe

Question 72

What describes when the microbiota is not doing the correct thing?

Answer 72

dysbiosis

Question 73

What is propionibacterium acnes associated with?

Answer 73

acne

Question 74

What is another name for atopic dermatitis?

Answer 74

eczema

Question 75

What appears to flare when there are increased quantities of Staphylococcus epidermidis and Staph aureus (but not sole cause)?

Answer 75

eczema (atopic dermatitis)

Question 76

What locations on the body does eczema favor?

Answer 76

- inside of elbow - location varies with age

Question 77

The human has (1) types of bacteria in the mouth

Answer 77

many (70 different genera)

Question 78

What type of bacteria resides in the human mouth?

Answer 78

both gram positive and negative

Question 79

The oral cavity is dominated by abundant (1) species of many kinds

Answer 79

streptococcus gram positive bacteria

Question 80

Streptococcus species in the oral cavity have what type of function?

Answer 80

- help metabolize carbohydrates - some can inhibit growth or more virulent, disease-causing strains

Question 81

What looks just like strep throat?

Answer 81

mono

Question 82

What part of the gut has transient bacteria from the mouth or stomach?

Answer 82

proximal esophagus

Question 83

What part of the gut is dominated by gram-positives (mostly streptococcus species) and also includes gram-negatives?

Answer 83

distal esophagus and stomach

Question 84

What part of the gut includes both gram positives (streptococcus and clostridium) and gram negatives (E. coli)?

Answer 84

small and large intestine

Question 85

What can change your microbiota for 6-12 months?

Answer 85

antibiotics

Question 86

What is located anterior nares to the larynx?

Answer 86

upper respiratory tract

Question 87

What is located from the larynx to alveoli?

Answer 87

lower respiratory tract

Question 88

Staphylococcus, streptococcus, and corynebacterium species can all be found where?

Answer 88

upper and lower respiratory tract

Question 89

The main source of microbes for the lungs appears to be the (1) in adults and the (2) and (3) in children?

Answer 89

1. oropharynx 2. nasopharynx 3. oropharynx

Question 90

Which respiratory tract has more organisms?

Answer 90

upper respiratory tract

Question 91

What is found in the nares of 1/3 of the population and what can this result in?

Answer 91

staphylococcus aureus - can result in infection of the bloodstream (sepsis) or skin around an infection

Question 92

The vaginal microbiota is predominantly what species?

Answer 92

Lactobacillus species

Question 93

What helps maintain healthy vaginal pH (<4.5) through the byproduct of lactic acid?

Answer 93

lactobacillus species

Question 94

What type of stain in lactobacillus?

Answer 94

gram-positive

Question 95

Is lactobacillus aerobic, FA, or anaerobic?

Answer 95

anaerobic

Question 96

What can having an adequate amount of lactobacillus protect against?

Answer 96

- overgrowth of other anaerobes and the symptomatic infections that result

Question 97

What are some ways to diagnose a bacterial infection?

Answer 97

1. rely on history and physical findings (80% of time, you'll know what's wrong) 2. in some cases, blood tests (CBC and other inflammatory mediators elevated) 3. sometimes we can send fluid out for analysis, culture and sensitivity (can take 24-48 hours to get results)

Question 98

What are some cultures we can use for bacterial infection analysis?

Answer 98

- urine - sputum - blood - stool - pus - CSF or joint fluid

Question 99

What are different tests for susceptibility testing of bacterial infections?

Answer 99

- agar dilution test - disk diffusion test

Question 100

What type of test does this describe: antibiotic is mixed with agar and bacteria are plated on antibiotic specific agar (one plate can test 32-36 bacteria ) - results are read at lowest concentration of antibiotic that inhibits growth

Answer 100

agar dilution test

Question 101

What type of test does this describe: bacteria is swabbed on agar plate, then filter discs are placed on top; after incubation, area around disks are measures (simple, reliable, and used frequently)?

Answer 101

disk diffusion test

Question 102

What is the result obtained on susceptibility tests?

Answer 102

minimum inhibitory concentration (MIC)

Question 103

What gives the lowest concentration of antibiotic that inhibits growth of that bacteria?

Answer 103

minimum inhibitory concentration (MIC)

Question 104

What are the results you can get from MIC?

Answer 104

- S=susceptible - I=intermediate - R=resistant

Question 105

What can be performed on a patient presenting with prolonged diarrhea?

Answer 105

stool cultures

Question 106

What bacteria are true pathogens and if found in blood cultures, could mean patient is septic?

Answer 106

- staphylococcus aureus - streptococcus pneumoniae - escherichia coli - pseudomonas aeruginosa - klebsiella pneumoniae - candida albicans